I really don't get why people say K mount wouldnt work for FF. It seemed to work pretty well on film - the very thing that created the concept of "full frame." Not to mention the little Russian m39 cameras. These were the same as m42, but with an even smaller diameter mount. Same register distance as m42 and K mount. And they covered full frame film just normally, and mirror wasn't a problem.
The idea that "FF mirror wouldn't fit" seems to be absurd. It fit in the past, why wouldnt it fit now? Also, they can redesign the mirror and shutter, brands have done it before.
With the SR mechanism, some say that FF lenses don't produce an image circle big enough for SR, but that also seems hard to believe. The SR doesn't move
that much. And besides, Pentax could just make future lenses with bigger image circle, if they need it. Some already have a pretty big image circle. Or make some lenses with in-lens stabilization which would automatically cancel out in-body SR, but keep the in-body SR for the lenses that have a big enough image circle. There are so many ways to do this. Pentax managed to make the SR double as AA filter. I'm sure they can figure out how to make it work for a slightly bigger sensor.
Would a FF camera be bigger than current crop sensor cameras? Quite possibly. Would it need some new innovation? Quite possibly. Would it be expensive? Very probably. Is it impossible? Nope.
Edit: then again, a lot of us don't even use SR, so if Pentax limits it, I wouldn't even mind.
Last edited by Na Horuk; 11-30-2013 at 08:53 AM.